The present invention relates to a device for use when analysing samples of organic body fluid that are drawn by suction from a patient into a so-called vacuum tube, which is held hermetically sealed with the aid of a rubber stopper or some corresponding sealing device.
A number of analyses are carried out daily on organic body fluids in hospital and like establishments, in order to establish the condition of the patients concerned. The majority of these analyses are carried out on blood serum and to this end there is first taken from the patient a small amount of his/her blood. The blood is normally taken with the aid of a so-called vacuum tube, i.e. a test tube which is sealed hermetically by means of a rubber stopper, in which a partial vacuum prevails. When the interior of the vacuum tube is placed in communication with a blood vessel, via a cannula, blood is automatically drawn into the tube by suction. The tube is then taken to a laboratory, or some like place, with the sealing stopper intact and with a partial vacuum still prevailing in the tube. In order to have access to the blood sample in the tube, it is necessary to remove the stopper. As a result of the air streams which flow past the stopper as the pressure in the tube is equalized by removal of the stopper, air mixed with blood fragments is liable to leave the tube and enter the ambient surroundings.
Part of the blood sample is normally extracted from the open vacuum tube with the aid of a pipette, comprising a cylindrical plastic plunger which is pressed down into the tube in sealing abutment with the inner wall surface thereof, so as to force blood into the pipette. If the plunger fails to seal precisely against the wall of the vacuum tube, blood is likely to spurt from the tube, around the sides of the plunger. Since the majority of analyses made on blood samples are carried out on blood serum, the sample must first be centrifuged in order to separate the blood serum from the blood corpuscles. Blood is also liable to spill during this procedure.
The aforedescribed blood-sample handling processes are unacceptable from the point of view of hygiene, since the laboratory personnel involved are in danger of being infected with diseases transmitted through the blood, for example such diseases as Aids and Yellow Fever. Moreover, the aforesaid handling or manipulating processes are highly time consuming.